Re: ALL() question

Julien Cigar wrote:
> 
> What I would like is a query that returns all the specimen_id of 
> this table which have _all_ the given test_bit_id. 
[snip]
> With the following I got a syntax error:
> select specimen_id 
> from specimen_test_bits 
> where test_bit_id = all(1,2,3,4);

It's expecting an array here. You'd have to write = all('{1,2,3,4}')
But that would have the same problem as...

> The following works but no rows are returned :
> select specimen_id 
> from specimen_test_bits 
> where test_bit_id = all(select id from test_bits where id in (1,2,3,4));

It's testing each row individually and of course one row can't match ALL 
four values.

What you want to do is count the distinct values. Something like:

SELECT  specimen_id
FROM foo
GROUP BY  specimen_id
HAVING  count(distinct test_bit_id) = 4
;

--   Richard Huxton  Archonet Ltd